The purpose of job interviews is for both parties to get an idea of whether it's a good fit between the company hiring and the job candidate. Unfortunately, sometimes interviewers can be tricky in the way they weed out candidates.

Financial site LearnVest interviewed hiring managers across the US and found some controversial methods they used to get information about applicants—and use that information against them. For example, one hiring manager places photos of children on his desk—photos that aren't of his own kids but of his nieces and nephews—to prompt candidates to get them talking about their families, so he can weed those out. Another admits to checking for wedding bands, even though discriminating against marital status is a huge no-no. And one hiring manager not only looks up candidates on social media networks, he adds them as friends to have access to their status updates and profiles.

As disheartening as this article slideshow is, you'll find some good tips here too (the biggest one being not to disclose personal information more than you need to). One clever idea: If you don't want to disclose your previous salary, you can say you signed a non-disclosure agreement (NDA) about your salary.